Examine source code of Night Mode Pro

{
  "version": "0.3.9",
  "manifest_version": 3,
  "name": "Night Mode Pro",
  "homepage_url": "https://mybrowseraddon.com/night-mode.html",
  "description": "Switch to night mode and the display is much easier on your eyes!",
  "web_accessible_resources": [
    {
      "matches": [
        "<all_urls>"
      ],
      "resources": [
        "data/content_script/inject.css"
      ]
    }
  ],
  "options_ui": {
    "open_in_tab": true,
    "page": "data/options/options.html"
  },
  "permissions": [
    "alarms",
    "storage",
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "109.0",
      "id": "{862f1187-5a4d-4b5c-b211-c5aea8a5c017}"
    }
  },
  "background": {
    "scripts": [
      "lib/config.js",
      "lib/chrome.js",
      "lib/runtime.js",
      "lib/common.js"
    ]
  },
  "action": {
    "default_title": "Night Mode Pro",
    "default_popup": "data/popup/popup.html",
    "default_icon": {
      "16": "data/icons/16.png",
      "32": "data/icons/32.png",
      "48": "data/icons/48.png",
      "64": "data/icons/64.png"
    }
  },
  "content_scripts": [
    {
      "all_frames": true,
      "matches": [
        "<all_urls>"
      ],
      "match_about_blank": true,
      "run_at": "document_start",
      "js": [
        "data/content_script/inject.js"
      ]
    }
  ],
  "commands": {
    "toggle-night-mode": {
      "description": "Toggle Night Mode (ON / OFF)",
      "suggested_key": {
        "default": "Ctrl+Shift+Y",
        "mac": "Command+Shift+Y"
      }
    },
    "add-to-whitelist": {
      "description": "Add Active Tab to Whitelist",
      "suggested_key": {
        "default": "Ctrl+Shift+U",
        "mac": "Command+Shift+U"
      }
    },
    "remove-from-whitelist": {
      "description": "Remove Active Tab from Whitelist",
      "suggested_key": {
        "default": "Ctrl+Shift+F",
        "mac": "Command+Shift+F"
      }
    }
  },
  "icons": {
    "16": "data/icons/16.png",
    "32": "data/icons/32.png",
    "48": "data/icons/48.png",
    "64": "data/icons/64.png",
    "128": "data/icons/128.png"
  }
}